I'm gonna add multiple levels in the middle sections, but I think I'm gonna try to leave a giant chasm-like area in the middle, so from any floor of any section you can look into it. But officially, I have no idea what I'm gonna do! :P
...no? I've never heard this before. There's certainly nothing in game which resembles one. It's quite possible that people have made up their own storylines and what not, but there's not one built into it.